It is the same for me. Your server is not finding them based upon your page code; are you sure you have uploaded them into the correct folder and sub-folder. Double check to confirm they are actually on the server, and in the right place.
images/london_web (sub folder for the full size picture)
the root directory, dragonontheweb. com, for the thumbnails
The banner appears it should be in a yet a different sub folder.